A false tsunami alarm has left one person dead and prompted hundreds of others to flee their homes in the Philippines, where natural disasters are frequent, a civil defence official says.

The cause of the sudden panic that hit Candelaria 88 kilometres south of Manila and other impoverished towns is still being investigated, said Henry Buzar, head of the area's disaster management council.

A 63-year-old woman who was fleeing on a motorised tricycle had a heart attack and died, Mr Buzar said, citing a local hospital.

"We really don't know where the rumour came from," he said late Tuesday.

"We suddenly received information that there were some people evacuating from the area."

"It was really chaotic. I told our staff to block the people and tell them there is no truth to these rumours but they told me they could not stop the rush of people."

Heavy rain may have triggered panic

Nearly a thousand people, many crammed into trucks and mini-buses, gathered at Candelaria's town hall for safety. But when no tsunami materialised, they went home after a few hours, he added.

Mr Buzar said he was puzzled by the sudden evacuation as there had been no report of any earthquake that might cause a tsunami, and many of those who fled did not even live on the coast.

The darkness and heavy rains brought on by the passage of Typhoon Matmo and anonymous mobile phone SMS messages may have helped trigger the confused exodus even though Matmo never hit land, disaster officials said.

At least 20 storms lash the country each year and earthquakes are a constant threat.

Last October an earthquake in the central Philippines killed more than 200 people. Super Typhoon Haiyan the following month sent a tsunami-like storm surge inland, eventually leaving more than 7,300 dead or missing.